Method and apparatus for distributing fluid into a turbomachine

ABSTRACT

An apparatus for distributing a fluid in a gas flow path inside a turbomachine, comprising: a device for introducing the fluid into the gas flow path; and wherein the device is positioned within the gas flow path. A method for installing an apparatus that will distribute a fluid in a gas flow path inside a turbomachine, the method comprising: machining a casing groove along an inner surface of a casing; machining at least one port into the casing that is in fluid communication with the casing groove; machining an internal cavity in at least one stator blade that is in fluid communication with the casing groove; machining at least one orifice, that is in fluid communication with the internal cavity, on an orifice surface of the stator blade; and coupling a fluid supply to the at least one port.

TECHNICAL FIELD

The current disclosed method and apparatus relate to an improvement inthe operation of a turbomachine. More specifically, the improvementrelates to the distribution of a fluid into the gas flow path inside ofa turbomachine.

BACKGROUND OF THE INVENTION

Turbomachines are used in a variety of useful applications. Aviation,shipping, power generation, and chemical processing have all benefitedfrom turbomachines of various designs. In regard to general terminology,the term “turbomachine” means any machine with one or more annular bladerows exchanging energy with the fluid crossing it. Examples ofturbomachines are: fans, certain types of compressors, turbines, pumpsand gas turbines.

Fluid materials such as water or cooled gas may be added to aturbomachine to increase the efficiency of the turbomachine. If water isadded to a compressor or the compressor section of a gas turbine, such aprocedure is identified as wet compression. Wet compression enablespower augmentation in turbomachine systems by reducing the work requiredfor compression of the inlet gas. This thermodynamic benefit is realizedwithin a compressor through “latent heat intercooling”, where water (orsome other appropriate liquid) added to the gas inducted into thecompressor cools that gas, through evaporation, as the gas with theadded liquid is being compressed. The added liquid can be conceptualizedas an “evaporative liquid heat sink” in this regard. The wet compressionapproach thus saves an incremental amount of work (which would have beenneeded to compress gas not containing the added liquid). The reductionin compressor work can be used to reduce the amount of fuel required toproduce the same net output of a gas turbine (thus increasing theefficiency), or to increase the incremental amount of work available forthe same gross output of the gas turbine, e.g. to drive a load attachedto a turbomachine such as a generator (in the case of a single shaftmachine) or to increase a compressor speed to provide more mass flow(which can have value in both single shaft and dual shaft machines).

An additional incremental contribution to power augmentation may berealized in the turbine section of a gas turbine, for instance, by asmall increase in mass flow provided by the added vaporized liquid. Afurther incremental contribution to power augmentation also appears tobe provided by an increase in gas flow which has been noted to occurwith a first, 10-20 gallon per minute, increment of liquid in a largeland-based power gas turbine. It should be noted that wet compressionreduces the firing temperature of the turbine if the amount of fuelsupplied is unchanged, and the reduced firing temperature reduces thegross output of the gas turbine. However, the reduction in compressorwork is greater than the reduction in gross output of the gas turbine sothat the net output of the gas turbine is increased. If the amount offuel supplied is increased in order to raise the temperature of thecooled (respective to dry gas compression) gas/evaporated liquid mixturedischarged from the compressor to the firing temperature of a gasturbine for dry compression; then the value realized from the wetcompression effect is greater than the value of the additional fuelneeded, resulting in value added to the operation of the system as awhole.

A risk of adding liquid to a turbomachine is blade erosion due to theimpact of the liquid material on the rotating and non-rotating blades.Another difficulty with wet compression (especially in large gas turbinesystems) relates to localized and non-uniform cooling (due tonon-uniform distribution of the added liquid) within the turbomachine,which can distort the physical components of the turbomachine system insuch a way as to cause damage from thermal stresses and from rubbing ofthe rotor against the inner wall of the housing and associated seals.

A further significant element of risk derives from the possibility ofthermal shock if (1) the turbomachine has essentially achievedthermodynamic equilibrium and (2) the liquid addition is abruptlyterminated without feed-forward compensation to the energy being addedto the turbomachine; the risk is derived from a potentially damaging andabrupt transient in the internal operating temperature of theturbomachine if the evaporative liquid heat sink is removed in thismanner.

Hydraulic atomizers that use the pressure of the liquid to producedroplets are commonly available, but either flow too little liquid orproduce droplets that are too large. Heating the liquid so that itflashes as it leaves the atomizer can decrease the droplet size, but therate of heat added to the liquid is equivalent to a large amount ofpower. Air-assisted atomizers are commonly available and can producesmall droplets at a high flow rate of liquid into the gas flow path of aturbomachine, but the hardware is bulky and cannot be inserted in thegas flow path of a turbomachine without significantly disturbing theflow. Therefore, atomizers are inserted in the outer casing in order toavoid disturbing the flow. But the liquid droplets tend to remain nearthe outer casing due to the small size and low momentum of the droplets,so the droplets are poorly distributed, and this severely limits theefficiency improvement of adding liquid to the gas flow stream of aturbomachine. Another disadvantage is that the compression of theatomizing air used in air-assisted atomizers requires a large amount ofpower.

What is needed is an approach and system which enable the addition ofliquid to a turbomachine to be implemented in turbomachine systems andwhich may reduce some or all of the disadvantages discussed above.

BRIEF DESCRIPTION OF THE INVENTION

An embodiment of the disclosed apparatus for distributing a fluid in agas flow path inside a turbomachine, relates to a device for introducingthe fluid into the gas flow path; and wherein the device is positionedwithin the gas flow path.

Additionally, another embodiment of the disclosed apparatus fordistributing a fluid in a gas flow path inside a turbomachine relates toat least one stator blade in at least one turbomachine stage; a fluidchannel in fluid communication with an interior of the stator blade; afluid supply in fluid communication with the fluid channel; and at leastone orifice located at an orifice surface of the stator blade, theorifice in fluid communication with the interior of the stator blade.

Furthermore, another embodiment of the disclosed apparatus fordistributing a fluid in a gas flow path inside a turbomachine relates toat least one stator blade in at least one turbomachine stage; a gaschannel; a fluid channel located at an interior of the stator blade, andconfigured to form a porous annulus around the gas channel to allowfluid from the fluid channel to pass into the gas channel; a fluidsupply in fluid communication with the fluid channel; and at least oneorifice located at an orifice surface of the stator blade, the orificein fluid communication with the gas channel.

Also, an embodiment for the disclosed apparatus for distributing a fluidin a gas flow path inside a turbomachine relates to at least one statorblade in at least one turbomachine stage, the stator blade comprising aporous material throughout its in interior, and the porous material isexposed on a portion the stator blade's max pressure surface and aportion of the stator blade's orifice surface; a fluid channel locatedat the interior of the stator blade, and configured to provide fluid tothe interior the stator blade; a fluid supply in fluid communicationwith the fluid channel; and wherein the stator blade is configured toadmit gas from the gas flow path of the turbomachine via the maxpressure surface and mix with fluid provided by the fluid channel, andthe atomized fluid exits the stator blade through the orifice surface.

In addition, another embodiment of a disclosed apparatus fordistributing a fluid in a gas flow path inside a turbomachine relates toat least one stator blade in at least one turbomachine stage, the statorblade comprising a cavity throughout a portion of its interior and aporous material on a portion of its orifice surface; a fluid channellocated at the interior of the stator blade, and configured to providefluid to the interior the stator blade; a fluid supply in fluidcommunication with the fluid channel; and wherein the stator blade isconfigured to accept fluid into its interior from the fluid channel, andallows the fluid to flow from the interior through the porous materialof the orifice surface and enter the gas flow path of the turbomachine.

Further, another embodiment of the disclosed apparatus for distributingan atomized fluid in a gas flow path inside a turbomachine relates to aheat exchanger configured to heat a fluid from an external source; atleast one stator blade in at least one turbomachine stage, the statorblade comprising a cavity throughout a portion of its interior; at leastone atomizer located at an orifice surface of the stator blade, theatomizer communicatively coupled the cavity; and wherein the statorblade is communicably coupled to the heat exchanger to accept heatedfluid into the cavity whereupon the heated fluid exits the cavitythrough the atomizer orifice and enters the gas flow path of theturbomachine.

A further embodiment of the disclosed apparatus for distributing a fluidin a gas flow path inside a turbomachine relates to a heat exchangerconfigured to heat a fluid from an external source; at least one statorblade in at least one turbomachine stage a tube located proximate to anorifice surface of the stator blade; at least one orifice located on aside of the tube, and the orifice communicatively coupled the cavity;and wherein the tube is communicably coupled to the heat exchanger toaccept heated fluid into the cavity whereupon the heated fluid exits thecavity through the orifice and enters the gas flow path of theturbomachine.

An additional embodiment of the disclosed apparatus for distributing afluid in a gas flow path inside a turbomachine relates to at least onestator blade in at least one turbomachine stage, the stator bladecomprising at least one chamber; the chamber comprising a vibrationplate that is operatively coupled to a vibration generator; a fluidchannel located at the interior of the stator blade, and communicablycoupled to the chamber; at least one orifice in fluid communication withthe chamber, and located at an orifice surface of the stator blade; afluid supply in fluid communication with the fluid channel; and whereinthe chamber is configured to provide a pulsation to a fluid supplied tothe chamber via the fluid channel, prior to the fluid exiting thechamber through the orifice to enter the gas flow path of theturbomachine.

Another embodiment of the disclosed apparatus for distributing a fluidin a gas flow path inside a turbomachine relates to at least one stageof a turbomachine, the stage comprising a 360 degree casing and at leastone stator blade extending radially from an inner surface of the casing;a casing groove located at the inner surface of the casing; a statorblade cavity located at an interior of the stator blade, and in fluidcommunication with the casing groove; a port located at the casing andin fluid communication with the casing groove; and at least one orificelocated at an orifice surface of the stator blade, the orifice in fluidcommunication with the stator blade cavity.

A further embodiment of the disclosed apparatus for distributing anatomized fluid in a gas flow path inside a turbomachine relates to atleast one stage of a turbomachine, the stage comprising a 360 degreecasing and at least one stator blade extending radially from an innersurface of the casing; a casing groove located at the inner surface ofthe casing; a stator blade cavity located at an interior of the statorblade, and in fluid communication with the casing groove; a port locatedat the casing and in fluid communication with the casing groove; and atleast one atomizer with at least one orifice located at an orificesurface of the stator blade, the orifice in fluid communication with thestator blade cavity.

An other embodiment of the disclosed apparatus for distributing a fluidin a gas flow path inside a turbomachine relates to at least one statorblade in at least one turbomachine stage; a tube located proximate to anorifice surface of the stator blade; at least one orifice located on aside of the tube; and a fluid supply in fluid communication with thebayonet-like tube.

An embodiment of the disclosed method for installing an apparatus thatwill distribute a fluid in a gas flow path inside a turbomachine relatesto machining a casing groove along an inner surface of a casing;machining at least one port into the casing that is in fluidcommunication with the casing groove; machining an internal cavity in atleast one stator blade that is in fluid communication with the casinggroove; machining at least one orifice, that is in fluid communicationwith the internal cavity, on an orifice surface of the stator blade; andcoupling a fluid supply to the at least one port.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the figures, which are exemplary embodiments, andwherein like elements are numbered alike:

FIG. 1 depicts a perspective view of a stator blade and air foils;

FIG. 2 depicts a top view of the stator blade and air foils;

FIG. 3 depicts a top view of another embodiment a stator blade and airfoil;

FIG. 4 depicts a front view of a air foil;

FIG. 5 depicts a perspective view of a stator blade with areverse-effervescent apparatus;

FIG. 6 depicts a top view of the stator blade from FIG. 5;

FIG. 7 depicts a perspective view of a stator blade comprising a porousmaterial;

FIG. 8 depicts a top view of the stator blade from FIG. 7;

FIG. 9 depicts a perspective view of a stator blade with a porousmaterial located at its trailing edge;

FIG. 10 depicts a top view of the stator blade from FIG. 9;

FIG. 11 depicts a schematic view of a turbomachine with a heatexchanger;

FIG. 12 depicts a perspective view of a stator blade with a pulsationapparatus;

FIG. 13 depicts a close up view of the pulsation apparatus from FIG. 12;

FIG. 14 depicts a side view of a stator blade and casing with a plenumcavity;

FIG. 15 depicts another embodiment of a stator blade and casing with aplenum cavity;

FIG. 16 depicts a side view of a stator blade and a bayonet-like tube;and

FIG. 17 depicts a top view of a stator blade and a bayonet-like tube.

DETAILED DESCRIPTION OF THE INVENTION

A detailed description of several embodiments of the disclosed apparatusand method are presented herein by way of exemplification and notlimitation with reference to FIGS. 1 through 17.

Air Foil Embodiment

It is desired to introduce a fluid into the gas flow path of aturbomachine. If the fluid is a liquid, then as the liquid evaporates itcools the gas, thereby increasing the efficiency of the turbomachine. Ifthe fluid is a cooled gas, then the cooled gas will cool the gas in theflow path of the turbomachine, thereby increasing the efficiency of theturbomachine, as well. It is also desired to atomize the liquid as itenters the flow path so that it is more readily able to evaporate.Atomizing a liquid means to break the liquid up into very smalldroplets. In addition, atomization of the liquid being added to theinterior of a turbomachine is important for preventing the formation oflarge droplets of liquid which may cause erosion of blades in theturbomachine. Atomization of the liquid also allows for a more uniformdistribution of the liquid throughout the turbomachine. FIG. 1 depictsone embodiment of the disclosed apparatus that helps atomize liquidadded to the interior of a turbomachine. FIG. 1 shows a perspective viewof one stator blade 10. Stator blades are also commonly known as vanes.Within the stator blade 10 are fluid channels 14. A liquid supply may beoperably connected to fluid channels 14. In one embodiment, the liquidmay be supplied to the fluid channels 14 via an external channel 20through the casing of the turbomachine. The external channel may coupleto an external liquid supply. The fluid channels 14 allow a liquid toexit the stator blade 10 through at least one orifice (not seen in FIG.1, but shown in FIG. 2) distributed radially along an orifice surface 18of the stator blade 10. This radial distribution of more than oneorifice on a surface of the stator blade 10 increases the radialdistribution of liquid throughout the gas flow path of the turbomachine.Typically, the leading edge of the stator blade has a higher pressurethan the trailing edge, which typically has a lower pressure. Usuallythe largest pressure drop across the stator blade would be between theleading edge and the trailing edge. However, stator blades may bedesigned where the high pressure surface may not coincide with theleading edge, and/or the low pressure surface may not coincide with thetrailing edge. Additionally, the largest pressure drops may not berequired for the herein disclosed embodiments. Therefore, “an orificesurface” on a stator blade shall be that surface that provides theminimum necessary pressure drop with respect to a location with adifferential pressure, such as a cavity in the stator blade or a surfaceon the stator blade, for an embodiment to function. Similarly, a surfaceidentified as a max pressure drop surface on a stator blade is thatsurface that provides a maximum pressure drop with respect to an orificesurface for the disclosed embodiment to function.

In an embodiment, the fluid channels 14 may split into plurality ofchannels 16, and each of the channels 16 may be in fluid communicationwith an orifice on the trailing edge of the stator blade 10. There maybe more or fewer channels 16 depending on various factors such as; butnot limited to, the size of stator blade and the amount of liquiddetermined necessary to be injected into the turbomachine. Locatedproximal to the orifice surface 18 are two air foils 22. The air foils22 assist in atomizing the liquid exiting at the orifice surface 18.This mechanism of atomization is analogous to the mechanism ofatomization known with respect to air-assisted atomizers, such asair-assisted nozzles. The mechanism of atomization in both air-assistedatomization and in the herein air foil disclosure is that a gas with ahigh relative velocity is made to interact with a liquid that has a lowrelative velocity. A sheer stress develops at the interface between thegas and the liquid. The sheer stress sets up perturbations in theliquid, which eventually causes the liquid to break up into smalldroplets, thereby atomizing the liquid. Thus, the gas that is travelingaround the stator blade 10 is analogous to the external atomizing airused in air-assisted atomization. The gas traveling around the statorblade is thus directed by the air foils 22 to interact with the liquidexiting the orifices on the orifice surface 18 of the stator blade 10.The gas has a very high velocity relative to the liquid exiting theorifice, and thus atomizes the liquid. In another embodiment, the airfoils 22 comprise the same materials used to make the stator blade 10.In one embodiment, the air foils 22 extend from the inner shell of theturbomachine, in a fashion similar to the way the stator blades 10extend from the inner shell of the turbomachine.

Delivering liquid to the interior of the stator blades and out throughorifices located at the orifice surface 18 of the stator blades has theadvantage of providing an extremely uniform distribution of the liquidthroughout the gas flow path of the turbomachine. This advantage isincreased when every stator blade in a stage has orifices providingliquid to the gas flow path of a turbomachine.

FIG. 2 shows a top view of the embodiment shown FIG. 1. In this view theorifice 26 can be seen on the orifice surface 18. In one embodiment,where the turbomachine is a 175 MW gas turbine, the flow rate of liquidto each stator blade in one stage is about 0.01 lbs/sec and the orifice26 is about 10 mils in diameter. FIG. 3 shows another embodiment of theair foil/stator blade arrangement. Stator blade 10 is shown with a fluidchannel 14 and an orifice 26. However, in this embodiment, rather thanthere being two air foils 22 adjacent to the stator blade 10, there is asingle bi-flow air foil structure 30. The single bi-flow air foilstructure 30 has at least one large orifice 34, which is larger andcollinear to each orifice 26. Thus, when liquid exits any of theorifices 26, it is acted upon by the gas being directed towards it bythe air foil structure 30. The liquid is then directed to and through arespective large orifice 34. In an embodiment, the orifice 26 may be 10mils in diameter and the larger orifice 34 may be about 100 mils indiameter. This process assists in atomizing the liquid. FIG. 4 is apartial front view of the air foil structure.

Thus, the above embodiments illustrate an apparatus for distributing anatomized liquid in a gas flow path inside a turbomachine. With orificesdistributed radially along the stator blade 10, the atomized liquid maybe distributed radially within the gas flow path of the turbomachine.

Reverse-Effervescent Effect Embodiment

It is known in effervescent systems that adding gas bubbles to a liquidassists in the atomization of that liquid. Gas bubbles are formed byflowing a gas stream through small openings in a surface that confines astream of liquid. However, this embodiment uses what may be described asa reverse-effervescent effect whereby a liquid flows through smallopenings in a surface that confines a gas, in order to produce anatomized liquid. The advantage of flowing the liquid through the smallopenings is that less pressure drop is then required to flow the gasstream, and the larger pressure drop for the liquid stream is providedby using less energy than would be required to provide the gas with thesame pressure drop.

FIG. 5 shows a reverse-effervescent embodiment of the disclosedapparatus. In this embodiment, a stator blade 10 is shown with anorifice surface 18. There is a fluid channel 14 that delivers liquid tothe stator blade and out the orifice surface 18 through an orifice 26.However, in this embodiment, there is also a gas channel 38 with anopening 42 either at or near a max pressure surface 46 of the statorblade 10. The fluid channel 14 forms an annulus 50 around the gaschannel 38. In one embodiment, the annulus has an outer diameter ofabout 0.125 inches and the porous surface of the annulus may be createdwith a stainless steel tube of about 0.5 inches in length, with adiameter of about 0.0625 inches with about 20 to 50 holes distributed onthe tube's surface, the holes being about 10 to 100 microns in diameter.This tube has an equivalent porosity in the range of about 0.01% toabout 0.4%, where porosity is the fraction of bulk volume of a materialconsisting of pore space. In another embodiment, the porous surface maybe created by a sintered stainless steel tube with an equivalentporosity of about 0.01% to about 0.4%. In still another embodiment, theporous surface may be a mesh screen with an equivalent porosity of about0.01% to about 0.4%. The liquid supplied to the fluid channel 14 may bea liquid under high pressure.

Gas from the turbomachine gas flow path enters the stator 10 through theopening 42 at or near the max pressure surface 46. The opening 42communicates the gas into gas channel 38. The high-pressure liquidenters through fluid channel 14 and passes through the porous annulus 50into the gas channel 38 where it mixes with the gas. There is a pressuredrop as the liquid passes through the porous annulus 50, which helpsatomize the liquid as it mixes with the gas in the gas channel 38. Themechanism of atomization used in a porous material such as a sinteredstainless steel, is similar to the atomization mechanization of simplypushing a liquid through an orifice in order to atomize the liquid. Asintered material, such as sintered stainless steel is comprised of manysmall pathways, which in essence act as many orifices. A relatively highpressure drop is required for the liquid to pass through the sinteredsurface, but the power requirement for a compressed liquid is less thanthat for a compressed gas at the same pressure drop. In one embodimentwhere the turbomachine is a 175 MW gas turbine, the pressure may beabout 3,000 psia.

The pressure drop across the stator blade 10 from the max pressuresurface to the orifice surface, is what pushes the liquid/gas mixturethrough the atomizer. The liquid/gas mixture exits the gas channel 38via the orifices 26, where another pressure drop occurs which alsoprovides more atomization to the liquid. FIG. 6 shows a top view of thestator blade 10 shown in FIG. 5.

In another embodiment of the reverse-effervescent apparatus, rather thanusing gas from the turbomachine entering the opening 42 of the statorblade 10, a gas from an external source may be supplied to the gaschannel 38. The gas may be supplied to the stator blade 10 in a mannersimilar to the way liquid is supplied to the fluid channel 14.

Porous Medium Embodiment

FIG. 7 illustrates another embodiment of the disclosed apparatus. Apartial cut-away view of a stator blade 10 is shown extending from theblades base 54, which is inserted into an inner shell of a turbomachine.Located within the stator blade is a fluid channel 14, which feeds waterto the interior of the stator blade 10. In this embodiment the interiorof a stator blade comprises a porous medium. In another embodiment, theporous medium may be a sintered stainless steel with a porosityequivalent to about 0.016% to about 0.4%. The porous medium of statorblade 10 is exposed to the gas flow path at the stator blade's maxpressure surface 46. Similarly at the orifice surface 18 of the statorblade, there is an exposed porous medium. The gas in the turbomachineenters the stator blade 10 at its max pressure surface 46 through theexposed porous medium. The gas mixes with the liquid supplied by thefluid channel 14 within the porous medium of the stator blade 10 wherethe liquid is atomized. The mixture of gas and atomized liquid exits thestator blade 10 through the orifice surface 18 and enters into the flowof the turbomachine. FIG. 8 shows a top view of the stator blade 10 fromFIG. 7.

FIG. 9 illustrates another embodiment of the disclosed apparatus. Statorblade 10 comprises a porous medium only on its orifice surface 18. Theinterior of the stator blade 10 comprises a stator blade cavity 48.Liquid is supplied to the stator blade cavity 48 via the fluid channel14. Therefore, when the fluid channel supplies liquid to the statorblade cavity 48, the liquid will exit the cavity 48 through the porousmedium on the orifice surface 18 where it is atomized as it enters theflow of the turbomachine. FIG. 10 shows a top view of the stator blade10 shown in FIG. 9. The orifice surface of the stator blade 10 comprisesa porous medium. The remainder of the outer surface of the stator blademay be standard non-porous material normally used in the fabrication ofstator blades.

Heat Exchanger Embodiment

In this embodiment, the use of at least one stage of stator blades withgas-assisted atomizers to introduce atomized liquid into the gas flowpath of a turbomachine is combined with a heat exchanger in order toboth heat the liquid to be atomized and to cool the gas used to assistin the atomization process. As discussed above, the work required by anaxial-flow turbomachine, such as, but not limited to, a compressor isreduced if the main compressor gas flow is cooled by injecting a liquidwhich evaporates in the gas flow path. The more evaporation that takesplace, the greater the cooling. Thus, to increase evaporation, it isdesired to heat the injected liquid so that it will more readilyevaporates due to a reduction of the surface tension in the liquiddroplets. Additionally, if the atomizing gas is cooled, its density andviscosity is increased. Therefore, when the atomizing gas with a veryhigh velocity interacts with the liquid, a larger sheer stress willdevelop on the interface between the gas and the liquid due to theincreased density and viscosity of the gas. This larger sheer stresssets up larger perturbations in the liquid, and causes an increasedatomization of the liquid. The amount of cooling capacity lost in thepre-heating of the liquid is much smaller than that gained in theevaporation process as the latent heat of vaporization is much greaterthan the specific heat.

FIG. 11 is a schematic drawing illustrating an embodiment of the heatexchanger apparatus. A turbomachine 62 is shown. A gas line 66 obtainsheated and compressed gas from a late stage area of the turbomachine.Liquid is pumped into the system through a fluid line 70 via a pump 74.Gas line 66 and fluid line 70 coupled to a heat exchanger 58. The heatexchanger 58 thus uses the heated and compressed gas from gas line 66 toheat the liquid from the fluid line 70. Similarly, the relatively coolliquid in fluid line 70 cools the heated and compressed gas in gas line66. Once through the heat exchanger 58 the cooled gas and heated liquidis directed to the stator blade cavity 48. Inside the cavity 48, thecooled gas is an atomizing gas because it has a high relative velocityas it interacts with the liquid in the cavity. The atomized liquid thenexits through orifices 26 of the gas-assisted atomizer on the orificesurface of the stator blades 10. The heat exchanger 58 may be selectedfrom, but not limited to, a coil heat exchanger, a plate heat exchanger,or shell-and-tube heat exchanger. An “atomizer”, as used in thisdocument, may be made up of simply an orifice, but may additionallyinclude additional hardware, such as, but not limited to: passages forassisting air, swirl vanes for the liquid, and other devices forassisting in atomizing liquid.

In one embodiment where the turbomachine 62 is a compressor that iscompressing about 1,000 lb/sec of gas, then approximately 10 lbs/sec ofliquid would be injected into the gas flow of the compressor via thestator blades 10 in a particular stage, and approximately 1 lb/sec ofatomizing gas would be used in the stator blades 10 in the particularstage. For example, if there are 100 stator blades 10 in the particularstage, and each stator blade 10 is configured with gas-assistedatomizers, then about 0.1 lb/s of water would be injected into the gasflow path per stator blade and each stator blade would use about 0.01lb/sec of atomizing gas.

Pulsation Embodiment

In this embodiment, the atomization of a liquid is accomplished bypulsing the liquid in a chamber that is in fluid communication with manysmall orifices. The pulsing is accomplished by vibrating a surface(vibration plate) of the chamber at a very high frequency. Severalvibration generators exist for vibrating the vibration plate, some ofthose are, but not limited to: piezoelectric actuators, bimetallicstrips, thermocouples producing temperature fluctuations, or capacitorsproducing electrostatic pulses.

The pulsing in the liquid chamber provides a mechanism for atomizing theliquid. Instead of using a high velocity gas to interact with a liquidand cause perturbations in the liquid thereby creating smaller droplets,this embodiment uses a more direct approach. The liquid is perturbed bythe vibration of the vibration plate, thereby causing the liquid tobreak up into smaller droplets. An advantage of using a piezoelectricactuator is that less auxiliary power is required as compared togas-assisted atomizers. Another advantage is the small size of thepulsating atomizer.

FIG. 12 shows an embodiment of the disclosed pulsation apparatus. Astator blade 10 is shown with a fluid channel 14 supplying liquid to twochambers 78. Each of the chambers 78 is acted upon by a piezoelectricactuator, 82. The piezoelectric actuators 82 repeatedly actuate causingthe vibration plate 86 to move in such a way that the liquid in thechambers 78 experience pressure waves, also known as pulsations, causedby the movement of the vibration plate 86. In one embodiment, the rateof pulsation would be about 1 to 10 MHz and the entering liquid pressurewould be about 30 psia. The action of the pressure waves on the liquidin the chambers 78 assist in atomizing the liquid as they leave throughsmall orifices 90. The orifices may be on the order of 10 microns indiameter. The thickness of the pulsating atomizer may be on the order of100 microns, and the length may be on the order of 5 inches. Such apulsating atomizer could be attached to the surface along the trailingedge of an otherwise unmodified stator vane without disturbing theaerodynamic properties of the stator vane.

FIG. 13 is a close up view of one of the piezoelectric actuators 82. Inthis view one chamber 82 supplied by a fluid channel 14, vibration plate86, piezoelectric actuator 82 and three small orifices 90 are shown. Thepiezoelectric actuator is repeatedly actuated to cause the vibrationplate 86 to move in such a way to create pressure waves in the liquid inthe chamber 78 such that when the liquid exits through the smallorifices 90, the liquid will be atomized.

Plenum Cavity Embodiment

Turbomachines may be newly manufactured to incorporate the embodimentsdiscussed above. The casing may be manufactured to supply stator blades10 with a liquid from an external supply. One known way to supply liquidto the internals of a turbomachine is to create a plenum cavity in thecasing during manufacture with a set number of external port connectionsfor receiving the liquid from an external supply. The plenum cavityextends around the entire circumference of the casing and is able todistribute the flow of liquid around the entire circumference of theturbomachine. However, in a service retrofit when this cavity has notbeen created as an integral part of the casing, a plenum cavity must becreated. In the past a plenum cavity was created using external pipingaround the casing with ports drilled through the casing to deliver theexternal liquid. This method is practicable when a small number of portscan be used, but in cases when a large number of ports are required,this method is not effective. For example, if external liquid is to becommunicated to the interior of every stator blade in a 100-blade stageof a turbomachine, then 100 ports would need to be drilled in thecasing. This high number of ports may give rise to a structuralintegrity risk, therefore it is desired to reduce the number of suchports.

FIG. 14 shows a plenum cavity embodiment of an apparatus for thedistribution of liquid to the internals of a turbomachine. Thisembodiment may be especially useful for a service retrofit of aturbomachine. In FIG. 14, a casing 94 and a stator blade 10 are shown.The interior surface of the casing has a casing groove 106circumferentially machined into the entire 360 degree circumference ofthe interior casing surface. In the currently disclosed embodiment, thecasing groove extends through the entire 360 degrees of the turbomachinecasing, however, in other embodiments there may be two casing grooveseach covering approximately 180 degrees of the casing, or three grooves,with each groove covering approximately 120 degrees of the casing, andso on. The casing groove 106 forms a plenum cavity 110 that extends theentire circumference of the turbomachine. The plenum cavity 110 may befed liquid from an external source by a single or multiple ports 114. Itis important to note there may be as few as one port 114 that suppliesthe entire circumference of the plenum 110, thus allowing for a limitednumber of ports to be drilled through the casing 94, and therebypreserving the structural integrity of the casing. The mating surfacesbetween the casing 94 and stator blade 10 may be sealed by a pair ofstatic seals 118, such as, but not limited to, a rope seal. Other sealsthat may be used include metals with a thermal expansion coefficientgreater than that of the casing or stator blades and high temperatureepoxies. In addition, there may exist an inter-blade gap due to thestator blades 10 being individual blades stacked against each other inassembly and thereby creating a potential leakage path in fluidcommunication with the groove 106. This inter-blade gap may be sealed bya static seal 122 between each pair of blades. The static seal 122 maybe, but is not limited to, a rope seal. Additionally, a seal made ofmetal with thermal expansion coefficient greater than that of the casingor stator blades may be used or a high temperature epoxy. The sealing ofthe aforementioned leakage paths is important as any leakage can causeuncontrolled atomization of the leaking fluid and the resulting leakedfluid can atomize at droplet sizes large than The plenum cavity 10 is incommunication with a stator, blade cavity 48. The stator blade cavity 48is in communication with orifices 26 of any of the previous atomizationembodiments near the orifice surface of the stator blade 10.

FIG. 15 shows another embodiment of the plenum cavity disclosure. Inthis embodiment, there is also a groove 102 machined into the topsurface of each stator blade in a stage of the turbomachine. In otherembodiments, fewer than all of the stator blades may have the statorblade groove 102 machined into it, for instance, every other statorblade may have a groove machined into, thus forming a larger plenumcavity at every other stator blade.

A method for retrofitting this embodiment to a turbomachine is describednext. An upper casing is removed from the turbomachine. A casing groove106 is machined into a 360 degree circumference of an internal surfaceof the casing. At least one port 114 is machined into the casing that isin fluid communication with the casing groove 106. A stator blade cavity48 and orifices 26 are machined into at least one stator blade in astage of the turbomachine. The turbomachine is reassembled with the atleast one port 114 coupled to an external channel which supplies liquidto the now formed plenum cavity 110.

In one embodiment, the casing groove 106 is 1.5 inches wide and 0.25inches deep. In an other embodiment where there is also a stator bladegroove, then the casing groove is 1.5 inches wide and 0.125 inches deep,and the casing groove is 1.25 inches long, 0.125 inches deep, and 0.25inches wide. The orifices 26 may be 10 mils in diameter.

Bayonet-Like Tube Embodiment

In another embodiment of the disclosed apparatus, a perforatedbayonet-like tube is placed in the wake region of one or many statorblades. Introducing liquid as an intercooling medium through abayonet-like tube in the wake region of one or many stator blades,minimizes any adverse aerodynamic impact. Another advantage of thisdisclosed embodiment is that this embodiment may be retrofitted ontoexisting turbomachines without extensive modification of othercomponents like the stator blade itself.

FIG. 16 shows an embodiment of the bayonet-like tube apparatus. A statorblade 10 is shown extending from a casing 94. Proximate to the orificesurface 18 of the stator blade 10 is a bayonet-like tube 130 alsoextending from the casing 94. The bayonet-like tube 130 has small outerdiameter so that it will be located completely within the wake of thestator blade 10. In one embodiment, the bayonet-like tube's 134 outerdiameter is about 0.25 inches. The bayonet-like tube 130 is perforatedwith orifices 26. The orifices 26 face in a direction for maximumatomization or for maximum wake momentum increase. FIG. 17 shows a topschematic view of a stator blade 10 and bayonet-like tube 130. Thedashed lines 134 represent the wake trail of the gas flow coming off thestator blade 10. As can be seen in FIG. 17, the bayonet-like tube 130 ispositioned within the wake shown by the dashed lines 134. In oneembodiment, the orifices may be about 10 mils in diameter. Anaerodynamic benefit may be attained by the bayonet-like tube if it fillsthe momentum defect of the wake with the momentum surplus of the liquidsupplied by the bayonet-like tube. The bayonet-like tube may be combinedwith the heat exchanger embodiment, in that instance instead oftransmitting the heated liquid and cooled gas through a stator bladefrom a heat exchanger, the heated liquid and cooled gas may betransmitted through a bayonet-like tube.

High-Pressure Area Nozzle Embodiment

It has been recently discovered that if the fluid enters the gas flowpath of the turbomachine near a high pressure surface of the statorblade, that atomization may also take place when the fluid exits thenozzle and interacts with the gas flow which is going in a directionopposite or nearly opposite to the fluid flow. Thus in anotherembodiment nozzles may be located on or near a high pressure surface ofthe stator blades, to introduce the fluid into the oncoming gas flow,thereby leading to good atomization of the fluid.

While the above embodiments have discussed introducing a liquid into thegas flow path of a turbomachine, similar advantages may be achieved byintroducing a cooled gas (such as, but not limited to cooled nitrogengas) into the flow path of the turbomachine in order to cool the gasflow within the turbomachine. Thus, all of the embodiments describedabove may include the introduction of a gas as well as a liquid into thegas flow path of a turbomachine.

While the embodiments of the disclosed method and apparatus have beendescribed with reference to exemplary embodiments, it will be understoodby those skilled in the art that various changes may be made andequivalents may be substituted for elements thereof without departingfrom the scope of the embodiments of the disclosed method and apparatus.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the embodiments of thedisclosed method and apparatus without departing from the essentialscope thereof. Therefore, it is intended that the embodiments of thedisclosed method and apparatus not be limited to the particularembodiments disclosed as the best mode contemplated for carrying out theembodiments of the disclosed method and apparatus, but that theembodiments of the disclosed method and apparatus will include allembodiments falling within the scope of the appended claims.

1. An apparatus for distributing a fluid in a gas flow path inside aturbomachine, comprising: a device for introducing the fluid into thegas flow path; and wherein the device is positioned within the gas flowpath.
 2. The apparatus of claim 1, wherein the atomized fluid enters thegas flow path at a low pressure surface proximal to a stator blade. 3.The apparatus of claim 1, wherein the fluid is distributed radially. 4.The apparatus of claim 1, wherein the turbomachine is a compressor. 5.The apparatus of claim 1, wherein the turbomachine is a gas turbine. 6.The apparatus of claim 1, wherein the device is a stator blade.
 7. Theapparatus of claim 1, wherein the device is a rotor blade.
 8. Theapparatus of claim 1 wherein the device is a tube placed in the wake ofa stator blade.
 9. The apparatus of claim 1 wherein the atomized fluidenters the gas flow path at a high pressure surface proximal to a statorblade.
 10. An apparatus for distributing a fluid in a gas flow pathinside a turbomachine, the apparatus comprising: at least one statorblade in at least one turbomachine stage; a fluid channel in fluidcommunication with an interior of the stator blade; a fluid supply influid communication with the fluid channel; and at least one orificelocated at an orifice surface of the stator blade, the orifice in fluidcommunication with the interior of the stator blade.
 11. The apparatusof claim 10, wherein the orifice surface is located at a low pressuresurface of the stator blade.
 12. The apparatus of claim 10, wherein theorifice surface is located at a high pressure surface of the statorblade.
 13. The apparatus of claim 10 further comprising: at least oneair foil located proximate to the at least one orifice, and configuredto direct flowing gas towards fluid exiting the at least one orifice.14. The apparatus of claim 13, wherein the at least one air foil is asingle bi-flow air foil structure.
 15. The apparatus of claim 10,wherein every stator blades in the at least one turbomachine stage isconfigured in the same manner as the at least one stator blade.
 16. Anapparatus for distributing a fluid in a gas flow path inside aturbomachine, the apparatus comprising: at least one stator blade in atleast one turbomachine stage; a gas channel; a fluid channel located atan interior of the stator blade, and configured to form a porous annulusaround the gas channel to allow fluid from the fluid channel to passinto the gas channel; a fluid supply in fluid communication with thefluid channel; and at least one orifice located at an orifice surface ofthe stator blade, the orifice in fluid communication with the gaschannel.
 17. The apparatus of claim 16, wherein the gas channel issupplied with gas from an external source.
 18. The apparatus of claim16, wherein the gas channel has an opening located at a max pressuresurface of the stator blade.
 19. The apparatus of claim 16, wherein theopening is located at the leading edge of the stator blade.
 20. Theapparatus of claim 16, wherein the orifice is located at a low pressuresurface of the stator blade.
 21. The apparatus of claim 16 wherein theporous annulus comprises a steel tube with more than about 20 holes ofgreater than about 10 microns in diameter.
 22. The apparatus of claim 16wherein the porous annulus comprises a steel tube with less than about50 holes of smaller than about 100 microns in diameter.
 23. Theapparatus of claim 16 wherein the porous annulus comprises sinteredstainless steel tube.
 24. The apparatus of claim 16 wherein the porousannulus comprises a tube formed from a steel mesh with a porosity ofgreater than about 0.016%.
 25. The apparatus of claim 16 wherein theporous annulus comprises a tube formed from a steel mesh with a porosityof less than about 0.4%.
 26. The apparatus of claim 16, wherein thefluid channel is configured to accept pressurized fluid from an externalsource.
 27. An apparatus for distributing a fluid in a gas flow pathinside a turbomachine, the apparatus comprising: at least one statorblade in at least one turbomachine stage, the stator blade comprising aporous material throughout its in interior, and the porous material isexposed on a portion the stator blade's max pressure surface and aportion of the stator blade's orifice surface; a fluid channel locatedat the interior of the stator blade, and configured to provide fluid tothe interior the stator blade; a fluid supply in fluid communicationwith the fluid channel; and wherein the stator blade is configured toadmit gas from the gas flow path of the turbomachine via the maxpressure surface and mix with fluid provided by the fluid channel, andthe atomized fluid exits the stator blade through the orifice surface.28. The apparatus of claim 27, wherein the max pressure surface is onthe leading edge of the stator blade.
 29. The apparatus of claim 27,wherein the orifice surface is on the low pressure surface of the statorblade.
 30. The apparatus of claim 27 wherein the porous material is asintered stainless steel.
 31. The apparatus of claim 30, wherein thesintered stainless steel has a porosity of greater than about 0.016%.32. The apparatus of claim 30, wherein the sintered stainless steel hasa porosity of less than about 0.4%.
 33. An apparatus for distributing afluid in a gas flow path inside a turbomachine, the apparatuscomprising: at least one stator blade in at least one turbomachinestage, the stator blade comprising a cavity throughout a portion of itsinterior and a porous material on a portion of its orifice surface; afluid channel located at the interior of the stator blade, andconfigured to provide fluid to the interior the stator blade; a fluidsupply in fluid communication with the fluid channel; and wherein thestator blade is configured to accept fluid into its interior from thefluid channel, and allows the fluid to flow from the interior throughthe porous material of the orifice surface and enter the gas flow pathof the turbomachine.
 34. The apparatus of claim 33, wherein the orificesurface is on a low pressure surface of the stator blade.
 35. Theapparatus of claim 33 wherein the porous material is a sinteredstainless steel.
 36. The apparatus of claim 34, wherein the sinteredstainless steel has a porosity greater than about 0.016%.
 37. Theapparatus of claim 34, wherein the sintered stainless steel has aporosity less than about 0.016%.
 38. An apparatus for distributing anatomized fluid in a gas flow path inside a turbomachine, the apparatuscomprising: a heat exchanger configured to heat a fluid from an externalsource; at least one stator blade in at least one turbomachine stage,the stator blade comprising a cavity throughout a portion of itsinterior; at least one atomizer located at an orifice surface of thestator blade, the atomizer communicatively coupled the cavity; andwherein the stator blade is communicably coupled to the heat exchangerto accept heated fluid into the cavity whereupon the heated fluid exitsthe cavity through the atomizer orifice and enters the gas flow path ofthe turbomachine.
 39. The apparatus of claim 38, wherein the orificesurface is on a low pressure surface of the stator blade.
 40. Theapparatus of claim 38, wherein the heat exchanger is further configuredto use gas from the turbomachine to heat the fluid.
 41. The apparatus ofclaim 40, wherein the heat exchanger is further configured to use thefluid to cool the gas from the turbomachine.
 42. The apparatus of claim41, wherein the stator blade is communicably coupled to the heatexchanger to accept heated fluid and cooled gas into the cavity suchthat the cooled gas assists in atomizing the heated fluid, prior to theheated fluid exiting the cavity through the orifice and entering the gasflow path of the turbomachine.
 43. The apparatus of claim 40, whereinthe gas is from a late stage area of the turbomachine.
 44. The apparatusof claim 38, wherein the stator blade is located at a mid stage of theturbomachine.
 45. The apparatus of claim 38, wherein the stator blade islocated at an early stage of the turbomachine.
 46. The apparatus ofclaim 38, wherein every stator blade in the at least one turbomachinestage is configured in the same manner as the at least one stator blade.47. An apparatus for distributing a fluid in a gas flow path inside aturbomachine, the apparatus comprising: a heat exchanger configured toheat a fluid from an external source; at least one stator blade in atleast one turbomachine stage; a tube located proximate to an orificesurface of the stator blade; at least one orifice located on a side ofthe tube, and the orifice communicatively coupled the cavity; andwherein the tube is communicably coupled to the heat exchanger to acceptheated fluid into the cavity whereupon the heated fluid exits the cavitythrough the orifice and enters the gas flow path of the turbomachine.48. An apparatus for distributing a fluid in a gas flow path inside aturbomachine, the apparatus comprising: at least one stator blade in atleast one turbomachine stage, the stator blade comprising at least onechamber; the chamber comprising a vibration plate that is operativelycoupled to a vibration generator; a fluid channel located at theinterior of the stator blade, and communicably coupled to the chamber;at least one orifice in fluid communication with the chamber, andlocated at an orifice surface of the stator blade; a fluid supply influid communication with the fluid channel; and wherein the chamber isconfigured to provide a pulsation to a fluid supplied to the chamber viathe fluid channel, prior to the fluid exiting the chamber through theorifice to enter the gas flow path of the turbomachine.
 49. Theapparatus of claim 48, wherein the chamber is configured to acceptpressurized fluid from the fluid channel.
 50. The apparatus of claim 49wherein the fluid is pressurized to about 30 psia.
 51. The apparatus ofclaim 48, wherein the pulsation frequency is greater than about 1 MHZ.52. The apparatus of claim 48, wherein the pulsation frequency is lessthan about 10 MHZ.
 53. The apparatus of claim 48, wherein the vibrationgenerator is a piezoelectric actuator.
 54. The apparatus of claim 48,wherein the vibration generator is a bi-metallic strip.
 55. Theapparatus of claim 48, wherein the vibration generator is a capacitor.56. The apparatus of claim 48, wherein every stator blade in the atleast one turbomachine stage is configured in the same manner as the atleast one stator blade. 57-76. (canceled)